There are over forty-seven million athletes under the age of twenty-four who participate in contact sports like football, basketball, hockey, soccer, boxing, and mixed martial arts (MMA) each year in the United States. Each of these young athletes is at risk for concussive traumatic brain injury (cTBI) and long-term brain dysfunction due to repeated head impact. These young athletes, with developing neurological systems, sustain a large portion of the 3.8 million cTBI occurring yearly and are at heightened risk of developing deleterious long-term neurological, physiological, and cognitive deficits. The head impact conditions responsible for cTBI and potential long-term deficits in athletes are unknown.